diff --git a/osu.Game/Audio/Effects/AudioFilter.cs b/osu.Game/Audio/Effects/AudioFilter.cs
index 5c318eb957..9446967173 100644
--- a/osu.Game/Audio/Effects/AudioFilter.cs
+++ b/osu.Game/Audio/Effects/AudioFilter.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Diagnostics;
 using ManagedBass.Fx;
 using osu.Framework.Audio.Mixing;
diff --git a/osu.Game/Audio/Effects/ITransformableFilter.cs b/osu.Game/Audio/Effects/ITransformableFilter.cs
index 02149b362c..fb6a924f68 100644
--- a/osu.Game/Audio/Effects/ITransformableFilter.cs
+++ b/osu.Game/Audio/Effects/ITransformableFilter.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Transforms;
 
diff --git a/osu.Game/Audio/IPreviewTrackOwner.cs b/osu.Game/Audio/IPreviewTrackOwner.cs
index 6a3acc2059..8ab93257a5 100644
--- a/osu.Game/Audio/IPreviewTrackOwner.cs
+++ b/osu.Game/Audio/IPreviewTrackOwner.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 namespace osu.Game.Audio
 {
     /// <summary>
diff --git a/osu.Game/Audio/ISampleInfo.cs b/osu.Game/Audio/ISampleInfo.cs
index 8f58415587..4f81d37e78 100644
--- a/osu.Game/Audio/ISampleInfo.cs
+++ b/osu.Game/Audio/ISampleInfo.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Collections.Generic;
 
 namespace osu.Game.Audio
diff --git a/osu.Game/Audio/ISamplePlaybackDisabler.cs b/osu.Game/Audio/ISamplePlaybackDisabler.cs
index 250e004b05..4167316780 100644
--- a/osu.Game/Audio/ISamplePlaybackDisabler.cs
+++ b/osu.Game/Audio/ISamplePlaybackDisabler.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Game.Skinning;
diff --git a/osu.Game/Audio/PreviewTrack.cs b/osu.Game/Audio/PreviewTrack.cs
index 8ff8cd5c54..cfedd581e5 100644
--- a/osu.Game/Audio/PreviewTrack.cs
+++ b/osu.Game/Audio/PreviewTrack.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using osu.Framework.Allocation;
 using osu.Framework.Audio.Track;
@@ -18,13 +16,13 @@ namespace osu.Game.Audio
         /// Invoked when this <see cref="PreviewTrack"/> has stopped playing.
         /// Not invoked in a thread-safe context.
         /// </summary>
-        public event Action Stopped;
+        public event Action? Stopped;
 
         /// <summary>
         /// Invoked when this <see cref="PreviewTrack"/> has started playing.
         /// Not invoked in a thread-safe context.
         /// </summary>
-        public event Action Started;
+        public event Action? Started;
 
         protected Track Track { get; private set; }
 
diff --git a/osu.Game/Audio/PreviewTrackManager.cs b/osu.Game/Audio/PreviewTrackManager.cs
index d19fdbd94c..a0537d7a4e 100644
--- a/osu.Game/Audio/PreviewTrackManager.cs
+++ b/osu.Game/Audio/PreviewTrackManager.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Audio.Track;
@@ -20,9 +18,9 @@ namespace osu.Game.Audio
 
         private readonly BindableDouble muteBindable = new BindableDouble();
 
-        private ITrackStore trackStore;
+        private ITrackStore trackStore = null!;
 
-        protected TrackManagerPreviewTrack CurrentTrack;
+        protected TrackManagerPreviewTrack? CurrentTrack;
 
         public PreviewTrackManager(IAdjustableAudioComponent mainTrackAdjustments)
         {
@@ -90,7 +88,7 @@ namespace osu.Game.Audio
         public class TrackManagerPreviewTrack : PreviewTrack
         {
             [Resolved(canBeNull: true)]
-            public IPreviewTrackOwner Owner { get; private set; }
+            public IPreviewTrackOwner? Owner { get; private set; }
 
             private readonly IBeatmapSetInfo beatmapSetInfo;
             private readonly ITrackStore trackManager;
diff --git a/osu.Game/Audio/SampleInfo.cs b/osu.Game/Audio/SampleInfo.cs
index 54b380f23a..19c78f34b2 100644
--- a/osu.Game/Audio/SampleInfo.cs
+++ b/osu.Game/Audio/SampleInfo.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -34,7 +32,7 @@ namespace osu.Game.Audio
                 Volume);
         }
 
-        public bool Equals(SampleInfo other)
+        public bool Equals(SampleInfo? other)
             => other != null && sampleNames.SequenceEqual(other.sampleNames);
 
         public override bool Equals(object obj)